Blackjack

Provably fair

Verify fairness

The session's seed decides every card. Its hash was committed before the first hand; the seed is revealed when the session ends. Each round's cards come from HMAC-SHA256 keyed by the seed over the round's number and the bettor's own seed.

Seed hash

890b66cbdcb8e0af87e514460777d74c063408b9d1836827ca29fdb4dad62788

Seed

b6178d8ac089228fb6a3d0a499b8187bf3a718efd225b52cd1a064c155122731 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

d70075242658f6143d45b27cf4544f6e

Commitment

Batch 58,316, Merkle root d57e9e990784f86f6bfeb723883c1d45f76fefcbd93fc7002a3fe45b7b5f1e08. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. ee7084527ff33370249fdcf00e5679ed8d8c1a45a24314b81f9bd841a78ad70d

Checked: the seed hash proves into the root.

To check it yourself, take the session's proof:

1. Hash the seed as above and compare it with the seed hash; prove the seed hash into the root with the Merkle path (keccak256, as for every match).
2. For each round: round seed = HMAC-SHA256(key = seed, "degen.house.round.v1" ‖ 0x00 ‖ u64be(length of the bettor's seed) ‖ bettor's seed ‖ u64be(round)).
3. Key ChaCha20 (RFC 8439, zero nonce) with the round seed and read little-endian 64-bit words; a card is the next word below 2⁶⁴ − 1 − ((2⁶⁴ − 1) mod 52), modulo 52.
4. Replay the round's actions with the game's rules: the cards and the payout must match.

The replay plays every hand rebuilt this way on the server from the same data, and marks any that does not rebuild as recorded.